The present disclosure relates to a battery housing for a vehicle driven by an electric motor, comprising a tray part having a bottom and side walls integrally formed thereon, and furthermore comprising a frame structure surrounding the outside of the tray part, wherein a gap remains between the side walls and the frame structure disposed on the outside thereof.
Vehicles driven by electric motors, such as passenger cars, industrial trucks or the like, use battery modules as power storage devices. Such battery modules are typically composed of a plurality of individual batteries. These batteries are what are known as high-voltage batteries. The accommodation of such battery modules necessary for operating such a vehicle is subject to certain requirements. It is essential that the battery module is, or the battery modules are, protected against outside conditions in the battery housing. In particular, these must meet the necessary safety requirements when exposed to crash-induced applied loads.
DE 20 2016 102 223 U1 discloses a battery housing comprising a tray part and a cover part detachably connected to the tray part. The two parts comprise an outwardly projecting mounting flange extending around the circumference on the mutually facing sides thereof.
A tray part for a battery housing can be produced cost-effectively by deep drawing a steel blank, for example. This causes the side walls integrally formed on the bottom of the tray part to be integrally formed on the bottom, forming a draft angle. This means that the side walls include an angle with the bottom which is a few degrees greater than 90°. Customarily, draft angles are approximately 3°. When such a configuration of the side walls is present, these include an angle with the bottom of 93°. This is necessary to be able to pull the molding tool out of the molded battery volume after the molding process.
In order to provide mechanical protection for the battery housing, and in particular for the battery module or battery modules accommodated therein, the tray part is or the tray parts are surrounded by a frame structure, which is disposed on the outer side with respect to the side walls. Such a frame structure is formed of individual profile sections assembled to form a frame profile. A battery housing comprising such a tray part is known from US 2011/0143179 A1. Light metal hollow chamber profiles extruded for weight savings purposes, and typically extruded aluminum profiles, are used as profile sections. The outer contour of the tray part in the region of the upper termination of the side walls thereof and the inside width of such a frame part are matched to one another. For cost reasons, it is standard procedure to use hollow chamber profile sections, in particular such that have a rectangular cross-sectional geometry. The inner side of the frame profile is supported on the outer side of the side walls of the tray part in the upper end section thereof, and more particularly directly below the transition of the side wall into the mounting flange projected outwardly therefrom. The mounting flange then rests on the upper side of a profile section of the frame profile. As a result, a gap is present between the outer side of the side walls and the outer side of the provided frame structure due to the inclined arrangement of the side walls.
The frame structure is provided to absorb impact, such as that which occurs during a collision, for example. The frame structure is thus intended to protect the battery volume present in the tray part against damage at least to a certain degree. At times, longitudinal and transverse braces are disposed in the tray volume for reinforcement purposes, the end faces of these braces being supported on the surfaces of the mutually facing side walls. Due to the inclined orientation of the side walls, the ends of such braces must be mitered at an angle that is complementary to the draft angle so that the end surfaces thereof rest against the side wall across the full surface of the end surfaces. These braces are provided to reinforce the tray part. The impact energy acting laterally on a profile section of such a frame profile in the event of a collision is transferred on to the side facing away from the impact via the brace or braces extending in the direction of the impact. This typically acts against an abutment. Finishing the ends of the braces used is a complex aspect of this concept. Moreover, it has been shown that the action of a force into the braces across the full surface only takes place when the profile section of the frame part receiving the impact has already been deformed to a certain degree.
Moreover, attaching the braces in the tray part is quite problematic. It is desirable that the ends of the braces are welded to the side walls. Due to the high heat input during welding, however, this causes significant warpage of the tray part. While it is possible to eliminate such warpage again in a subsequent straightening process, this necessitates an additional process step during production.
The foregoing examples of the related art and limitations therewith are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent to those of skill in the art upon a reading of the specification and a study of the drawings.